JP2001305554A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid cutting of lines by a spacer. SOLUTION: A protruding body to hold the gap between substrates is formed on the liquid crystal side face of one substrate of substrates disposed facing each other through the liquid crystal, and the protruding body is arranged to avoid superimpose on the signal line formed on the liquid crystal side face of at least one substrate of the substrates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal display device, and more particularly to a spacer for holding a gap between substrates opposed to each other via a liquid crystal.

[0002]

2. Description of the Related Art A liquid crystal display device comprises a display section comprising a group of a large number of pixels in the direction in which the liquid crystal spreads, each of the transparent substrates facing each other via a liquid crystal as an envelope.

The quality of display can be improved by making the thickness of the liquid crystal uniform over the entire display area.

For this reason, a plurality of spacers called, for example, spherical beads are interposed between the transparent substrates in the display section.

[0005] Each of these beads is previously mixed in the liquid crystal when the liquid crystal is sealed between the transparent substrates, and is arranged between the transparent substrates together with the liquid crystal. I have.

[0006]

However, such beads cannot be displaced between the transparent substrates when the respective transparent substrates are displaced in a direction in which the transparent substrates are separated due to, for example, vibration of the liquid crystal display substrate. Did not.

[0007] The fluctuation of the beads sometimes interferes with the thin film transistor formed in each pixel region, causing a disconnection or the like in the electrode.

In addition, not only the thin film transistor but also a gate signal line for driving the thin film transistor or a drain signal line for supplying a video signal to a pixel electrode through the thin film transistor interferes with each other, causing the disconnection. It was a cause for rush.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid crystal display device that does not cause disconnection by a spacer.

[0010]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, typical ones will be briefly described as follows.

That is, the liquid crystal display device according to the present invention comprises:
Basically, a projection is provided on a liquid crystal side surface of one of the substrates disposed to face each other with a liquid crystal therebetween to maintain a gap between the other substrate and the projection. The liquid crystal display is arranged so as not to overlap with signal lines formed on at least one liquid crystal side surface of each of the substrates.

In the liquid crystal display device thus configured, even if the projection vibrates due to the fluctuation of one substrate with respect to the other substrate due to external vibration, the projection is not on the drain signal line. No damage or breakage of the wire will occur.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the liquid crystal display device according to the present invention will be described below with reference to the drawings. [Embodiment 1] FIG. 1 is a plan view showing an embodiment of a liquid crystal display device according to the present invention. FIG. 2 shows II-
It is sectional drawing in the II line.

FIG. 1 shows one of the pixel regions arranged in a matrix. Therefore, the left, right, upper, and lower pixel regions have the same configuration as the pixel region in the drawing.

In the figure, a gate signal line GL extending in the x direction in the figure is formed on the liquid crystal side surface of the transparent substrate SUB1.

The gate signal line GL is formed below the pixel area, and is made of, for example, chromium or an alloy thereof.

An insulating film GI made of, for example, a SiN film is formed on the surface of the transparent substrate SUB1 so as to cover the gate signal line GL.

The insulating film GI functions as an interlayer insulating film of a gate signal line GL for a drain signal line DL described later, functions as a gate insulating film for a thin film transistor TFT described later, and a function described later. The capacitive element Cadd has a function as a dielectric film.

On the upper surface of the insulating film GI, for example, in the region where the thin film transistor TFT is formed, that is, in the region overlapping with a part of the gate signal line GL, for example, a-
A semiconductor layer AS made of Si is formed.

A drain electrode S is formed on the upper surface of the semiconductor layer AS.
By forming D2 and source electrode SD1,
An MIS transistor having an inverted staggered structure using a part of the gate signal line GL as a gate electrode is formed. Each of the electrodes is formed simultaneously with the formation of the drain signal line DL.

That is, a drain signal line DL extending in the y direction is formed in the left portion of the pixel region in the drawing. This drain signal line DL is formed of, for example, chromium or an alloy thereof.

Then, a part of the drain signal line DL extends to above the semiconductor layer AS to form a drain electrode SD
2, and a source electrode SD1 is formed at a distance from the drain electrode SD2 at an interval corresponding to the channel length.

On the upper surface of the insulating film GI, a drain signal line DL shown in the figure, another drain signal line (not shown) adjacent to this signal line, and a gate signal line G shown in the figure are provided.
L and the other gate signal line (not shown) adjacent to this signal line.
A pixel electrode PX made of an (Indium-Tin-Oxide) film is formed.

The pixel electrode PX is formed so as to overlap with the source electrode SD1 of the thin film transistor TFT, so that the pixel electrode PX is connected to the source electrode SD1.

A part of the pixel electrode PX is formed so as to overlap with another gate signal line adjacent to the gate signal line GL shown in the figure, and the insulating film GI is provided between the gate electrode and the other gate signal line. Is formed as a dielectric film.

The capacitive element Cadd is provided for, for example, accumulating a long video signal supplied to the pixel electrode PX when the thin film transistor TFT is turned off.

Then, the transparent substrate S thus configured
A protective film PSV made of, for example, SiN is formed on the surface of UB1.
Are formed over the entire area, and mainly the thin film transistor TF
The direct contact of T with the liquid crystal is avoided.

Further, an alignment film ORI1 is formed on the upper surface of the protective film PSV, and regulates the initial alignment direction of the liquid crystal in direct contact with the film.

The transparent substrate SUB1 constructed as described above is called a so-called TFT substrate, and a so-called F substrate is provided through a liquid crystal.
It is arranged to face another transparent substrate SUB2 called an IL substrate.

As shown in FIG. 2, a black matrix BM (also shown in FIG. 1) is formed on the liquid crystal side surface of the other transparent substrate SUB2 so as to define a pixel area. The opening of the matrix BM is red,
One of green and blue filters FIL is formed.

The black matrix BM
Also, a so-called flat film OC for covering the filter FIL and flattening the surface is formed. This flat film O
C is made of, for example, a resin material, and by forming it by coating, the step of the black matrix BM and the filter FIL does not appear on its surface.

A projection PRO is formed on the surface of the flat film OC. The protrusion PRO is formed of the TF
This is for forming a uniform gap with the T substrate, and is provided so that the thickness of the liquid crystal layer is uniform over the entire display area.

The protrusion PRO is formed by, for example, selectively etching a resin film formed on the surface of the flat film OC by a so-called photolithography technique, so that the protrusion PRO is formed at a predetermined position in the display area (or the pixel area). It can be formed with high accuracy. In addition, if care is taken to ensure that the thickness of the resin film formed on the surface of the flat film OC is sufficiently uniform, the heights of the formed projections can be made uniform with high accuracy.

As shown in FIG. 1, each of the projections is formed at a slight distance from the drain signal line DL, and a part thereof is formed so as to overlap the pixel electrode PX. .

The reason for this is to prevent the protrusion PRO from being arranged so as to overlap with the drain signal line DL, and to prevent the protrusion PRO from entering the pixel region.

For this reason, the protrusion PRO is formed so as to be superimposed on the black matrix BM, so that it cannot be seen from the display surface side.

In the liquid crystal display device configured as described above, even if the protrusion PRO vibrates due to the fluctuation of one substrate with respect to the other substrate due to external vibration, for example, it is not on the drain signal line DL. The damage or disconnection of the drain signal line DL does not occur.

Further, the flat film OC and the protrusion PRO
The common electrode CT common to each pixel is provided on the surface of
An orientation film ORI2 is formed on the upper surface of the ITO film.

A reference signal (voltage) is applied to the counter electrode CT, and an electric field (in a direction perpendicular to the transparent substrate: between the counter electrode CT and the pixel electrode PX to which a video signal (voltage) is applied). (Referred to as a vertical electric field method), and the light transmittance of the liquid crystal is controlled by this electric field.

In the above-described embodiment, the protrusion PRO arranged near the drain signal line DL is formed so as to partially overlap the pixel electrode PX. However, as shown in FIG. 3, it goes without saying that a notch CU may be partially provided in the pixel electrode PX, and the protrusion may be positioned in this notch. This is to prevent the damage of the pixel electrode due to the protrusion from extending to a substantial pixel region surrounded by the black matrix.

In the above-described embodiment, the protrusion PRO is formed in a portion close to the drain signal line DL. However, as shown in FIG.
It is needless to say that the present invention is not limited to this, and may be formed in a portion close to the gate signal line GL. In this case, it goes without saying that a notch may be provided in the pixel electrode as shown in FIG. [Embodiment 2] FIG. 5 is a plan view showing another embodiment of the liquid crystal display device according to the present invention, and corresponds to FIG. FIG. 6 is a diagram showing a cross section taken along line VI-VI of FIG.

The figure is called a so-called lateral electric field system, in which the counter electrode CT is formed on the TFT substrate side together with the pixel electrode PX, and the light of the liquid crystal is generated by an electric field having a component substantially parallel to the TFT substrate between these electrodes. The transmittance is controlled.

The same reference numerals as those in FIG. 1 have the same functions. 1 is different from that of FIG. 1 in the counter electrode CT and the counter voltage signal line CL connected thereto.

The counter voltage signal line CL extends, for example, in the x direction in the figure across the center of the pixel region, and integrally forms a counter electrode CT extending in the y direction in the figure.

For example, three counter electrodes CT are formed, one of which is formed across the center of the pixel region, and the other two are formed adjacent to the drain signal line DL, respectively.

The counter voltage signal line CL and the counter electrode CT are formed at the same time as, for example, the gate signal line GL, and are therefore formed in the same layer and of the same material as the gate signal line GL.

On the other hand, the pixel electrode PX is formed, for example, in the same layer as the drain signal line DL, and is formed to extend between the respective counter electrodes CT in the y direction in the drawing.

As a result, the pixel electrode PX is composed of two lines, one of which is connected at one end to the source electrode SD1 of the thin film transistor TFT, and the other is connected on the counter voltage signal line CL. Connected to each other.

The connecting portion of each pixel electrode PX on the counter voltage signal line CL has a relatively large area, and in this portion, a capacitive element Cadd is formed between the pixel electrode PX and the counter voltage signal line CL. I have.

Further, the transparent substrate SU configured as described above
A protective film PSV is formed on the surface of B1, and an alignment film ORI1 is formed on the surface.

In such a configuration, similarly to the first embodiment, the protrusions PRO are formed on the other transparent substrate facing the TFT substrate, and each of the protrusions PRO is formed as shown in FIG. It is formed with a slight interval from the drain signal line DL, and a part thereof is formed so as to overlap the counter electrode CT.

The protrusion PRO is formed so as to overlap the black matrix BM.

In the above-described embodiment, the protrusion PRO arranged near the drain signal line CT is formed so as to partially overlap the counter electrode CT. However, as shown in FIG. 7, a cutout CU is provided in the counter electrode CT, and the protrusion PRO is positioned at the cutout CU to position the counter electrode C.
Needless to say, they may be formed without overlapping with T.

In the above-described embodiment, the protrusion PRO is formed in a portion close to the drain signal line DL. However, as shown in FIG.
It is needless to say that the present invention is not limited to this, and may be formed in a portion close to the gate signal line GL. [Embodiment 3] FIG. 9 is a diagram showing another embodiment of the liquid crystal display device according to the present invention.

FIG. 7 is a cross-sectional view taken along one of the gate signal lines GL of the in-plane switching mode liquid crystal display device, and a projection PRO is formed on the transparent substrate SUB2 side.

The protrusions PRO are arranged so as to be overlapped with spacers (referred to as PRO1: existing in a region B in the drawing) for maintaining a gap between the substrates, and especially at both ends of each gate signal line GL. PRO (PRO2)
(Existing in the area A in the figure).

Further, conductive layers 21 are formed on the liquid crystal side surface of the transparent substrate SUB2 so as to overlap with the respective gate signal lines GL on the transparent substrate SUB1 side.

In this case, each of the conductive layers 21 is necessarily formed in a state of covering the protrusion PRO2, and is electrically connected to the gate signal line GL opposed to the protrusion PRO2. The connection will be made.

Therefore, the gate signal line GL is provided with a bypass circuit separately from the original signal line, and even if a break occurs in the gate signal line GL, the disconnection is protected by the bypass circuit. The effect is obtained.

In the above-described embodiment, the protection circuit for the gate signal line GL has been described. However, it goes without saying that the present invention can be applied to the case where the drain signal line DL is protected. In this case, the gate signal line G in FIG.
L is replaced by the drain signal line DL. [Embodiment 4] FIG. 10 is a view showing another embodiment of a vertical electric field type liquid crystal display device according to the present invention.

FIG. 9 shows each gate signal line G of the liquid crystal display device.
FIG. 13 is a cross-sectional view taken along one of L, and includes a projection PRO fixed to the transparent substrate SUB2 side.

The protruding body PRO includes a protruding body (referred to as PRO1; which exists in a region B in the drawing) for maintaining a gap between the substrates and a protruding body disposed in the vicinity of a sealing material SL for sealing each substrate. (Referred to as PRO2: existing in the area A in the figure).

The projection PRO2 is formed simultaneously with the projection PRO1 at the time of formation.

On the liquid crystal side surface of the transparent substrate SUB2, a common electrode CT common to the pixels is formed so as to cover the projections PRO.

Further, the projection P is provided on the surface of the transparent substrate SUB1 which is in contact with at least one of the projections PRO2.
A conductive layer 23 electrically connected to the opposing electrode 22 covering RO2 is formed.

The conductive layer 23 extends beyond the sealing material SL on the transparent substrate SUB1 and is connected to a terminal for supplying a reference signal to the counter electrode 22.

Therefore, when a reference signal is supplied to the terminal on the transparent substrate SUB1, the reference signal is supplied to the counter electrode 22 on the transparent substrate SUB2 side via the protrusion PRO2.

The liquid crystal display device configured as described above has an effect that it is not necessary to particularly provide a conductive means for leading the counter electrode 22 to the surface of the transparent substrate SUB1. [Embodiment 5] FIG. 11 (a) shows a display area AR.
FIG. 4 is a diagram illustrating a protrusion PRO arranged so as to overlap a black matrix BM that outlines each pixel.

The projections PRO thus arranged are arranged uniformly over the entire display area, but one projection PRO is arranged for substantially the same number of pixels adjacent to each other. I have.

The number of the protrusions PRO in the display area is reduced, and accordingly, the disturbance of the alignment caused by the protrusions PRO is reduced.

As a result, light leakage (particularly in the case of black display)
This has the effect of preventing contrast due to [Embodiment 6] FIG. 11B shows a case where the number of protrusions PRO in the display area is reduced and the arrangement thereof is not uniform and is random (without uniformity), as in Embodiment 5. This is different from the fifth embodiment.

As a characteristic of human vision, when a light leakage portion occurs in a repetitive pattern, it is easy to recognize it. Therefore, the inconvenience is solved by disposing the spacers without uniformity. [Embodiment 7] FIG. 12 is an explanatory view showing another embodiment of the liquid crystal display device according to the present invention.

In the same figure, another transparent substrate SUB1 opposed to the transparent substrate SUB2 on the side on which the protrusion PRO is fixed.
The adhesive 30 is interposed in the abutting portion of the projection PRO between them.

The contact portions of the projections PRO are contact portions between the alignment films, and since these are made of the same material, there is a disadvantage that the fixing force is weak.

Therefore, as the adhesive 30, for example, Si
By using a coupling agent, each transparent substrate SUB
1 and SUB2, the reliability of maintaining the gap can be secured.

Next, one embodiment of a method of manufacturing a liquid crystal display device having such a configuration will be described with reference to FIG. Step 1. A projection PRO is formed on one of the substrates, and an alignment film is formed covering the projection PRO as well (FIG. 7A). Step 2. The substrate is brought close to the container filled with the adhesive, and the surface of the adhesive 30 is brought into contact with the top of the protrusion PRO (FIG. 4B). Step 3. Thereby, the adhesive 30 is attached to the top of the protrusion PRO.
Is applied (FIG. 3C). Step 4. The substrate is arranged so as to face another substrate (FIG. 4D). Step 5. By applying heat treatment, the adhesive 30 is cured. As a result, the protrusions PRO are fixed to the respective substrates (FIG. 9E).

Another embodiment of the method of manufacturing the liquid crystal display device having the above-described configuration will be described with reference to FIG. Step 1. A projection PRO is formed on one of the substrates, and an alignment film is formed covering the projection PRO as well (FIG. 7A). Step 2. An apparatus provided with a roller 31 in a container filled with the adhesive 30 is prepared, and the adhesive adhering to the surface thereof is applied to the top of the protrusion PRO by the rotation of the roller 31 (FIG. 2B). Step 3. Thereby, the adhesive 30 is attached to the top of the protrusion PRO.
Is applied (FIG. 3C). Step 4. The substrate is arranged so as to face another substrate (FIG. 4D). Step 5. By applying heat treatment, the adhesive 30 is cured. As a result, the protrusions PRO are fixed to the respective substrates (FIG. 9E). It is needless to say that this embodiment may be applied to the configuration of the liquid crystal display device of each embodiment described above. [Embodiment 8] FIG. 15 is an explanatory view showing another embodiment of the liquid crystal display device according to the present invention.

In the figure, a recess 40 into which the top of the projection PRO is fitted is provided on the other substrate side facing the substrate to which the projection PRO is fixed.

The recess 40 is formed, for example, by a TFT
It is formed on the protective film 41 on the side of the substrate 1A, and has a so-called reverse tapered shape having a large area on the bottom surface side with respect to the surface thereof.

In the case of such a configuration, the protrusion PRO
Is similar to a state in which the top is cut into the concave portion 40 and is adhered to the transparent substrate SUB1.

FIG. 16 shows another embodiment having the same effect. In this embodiment, means having the same function as the recess 40 is formed by a groove between a pair of signal lines (wirings) 42. Things.

In this case, the opposing sides of each signal line have an inversely tapered shape.

[0083]

As is apparent from the above description,
According to the liquid crystal display device of the present invention, disconnection due to the spacer is not caused.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a pixel region of a liquid crystal display device according to the present invention.

FIG. 2 is a cross-sectional view taken along line II of FIG.

FIG. 3 is a plan view showing another embodiment of the pixel region of the liquid crystal display device according to the present invention.

FIG. 4 is a plan view showing another embodiment of the pixel region of the liquid crystal display device according to the present invention.

FIG. 5 is a plan view showing another embodiment of the pixel region of the liquid crystal display device according to the present invention.

FIG. 6 is a sectional view taken along line VI-VI of FIG. 5;

FIG. 7 is a plan view showing another embodiment of the pixel region of the liquid crystal display device according to the present invention.

FIG. 8 is a plan view showing another embodiment of the pixel region of the liquid crystal display device according to the present invention.

FIG. 9 is a sectional view showing another embodiment of the liquid crystal display device according to the present invention.

FIG. 10 is a sectional view showing another embodiment of the liquid crystal display device according to the present invention.

FIG. 11 is a plan view showing another embodiment of the liquid crystal display device according to the present invention.

FIG. 12 is a plan view showing another embodiment of the liquid crystal display device according to the present invention.

FIG. 13 is a process chart showing one embodiment of a method for manufacturing a liquid crystal display device according to the present invention.

FIG. 14 is a process chart showing another embodiment of the method of manufacturing the liquid crystal display device according to the present invention.

FIG. 15 is a sectional view showing another embodiment of the liquid crystal display device according to the present invention.

FIG. 16 is a sectional view showing another embodiment of the liquid crystal display device according to the present invention.

[Explanation of symbols]

SUB: substrate, GL: gate signal line, DL: drain signal line, PX: pixel electrode, CT: counter electrode, PRO: protrusion, TFT: thin film transistor, BM: black matrix.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Ishii 3300 Hayano, Mobara-shi, Chiba Prefecture Within Hitachi, Ltd. Display Group (72) Inventor Masayuki Hikiba 3300, Hayano, Mobara-shi, Chiba Prefecture Within Hitachi, Ltd. Display Group F term (reference) 2H089 LA12 LA16 NA14 QA01 QA16 TA13 2H091 FA35Y GA06 GA08 GA13 GA16 2H092 GA14 HA04 JA26 JB58 JB61 KA05 KB04 KB25 MA13 NA15 PA03 PA09 5C094 AA32 BA03 BA43 EA04 EB02 EC03 HA08

Claims (6)

[Claims] 1. A liquid crystal-side surface of one of the substrates opposed to each other with a liquid crystal interposed therebetween is provided with a projection for maintaining a gap between the substrate and the other substrate. A liquid crystal display device, wherein the liquid crystal display device is arranged so as to avoid overlapping with a signal line formed on at least one liquid crystal side surface of each of the substrates. 2. The liquid crystal display device according to claim 1, wherein a black matrix is formed on at least one of the substrates, and the protrusion is overlapped with the black matrix. 3. A switching element driven by supply of a scanning signal from a gate signal line to a pixel area on a liquid crystal side surface of one of the substrates arranged to face each other with a liquid crystal interposed therebetween, and And a pixel electrode to which a video signal is supplied from a drain signal line via a switching element, a gate signal line, and a drain signal line on a liquid crystal side surface of the other of the substrates. A liquid crystal display device characterized by having no projections. 4. The liquid crystal display device according to claim 3, wherein a counter electrode for generating an electric field between the pixel electrode and the pixel electrode is formed on the other substrate. 5. The liquid crystal display device according to claim 3, wherein a counter electrode for generating an electric field between the pixel electrode and the pixel electrode is formed on one of the substrates. 6. The liquid crystal side surface of the other substrate is formed with a black matrix defining a pixel area, and the projection is formed so as to overlap with the black matrix. Liquid crystal display device.